Absorbent articles have been used in various fields such as hygienic materials such as disposable diaper, sanitary napkin and incontinence pad; urine-absorbent materials for pets; materials for civil engineering and construction such as packing materials; drip absorbents; food freshness retaining materials such as cold-reserving agents; horticultural articles such as water-retaining materials for soils; and the like.
However, there are some problems in the hygienic materials such that an absorbent article which has absorbed a body fluid, especially urine, blood, sweat or the like generates an unpleasant odor. It is thought that the odor is a corruptive odor generated by degrading the components of a body fluid such as urea, protein or the like with an enzyme, which is produced by bacteria that are present on skin and in the gastrointestinal tract.
In order to suppress the generation of these odors, there has been proposed an antimicrobial high-water-absorbent resin, obtained by crosslinking copolymerization of a phosphonium salt monomer component having an antimicrobial property with a monomer component which is copolymerizable with the phosphonium salt component and capable of forming a high-water-absorbent resin after the polymerization (for example, see Patent Publication 1). However, there are some disadvantages in this antimicrobial high-water-absorbent resin, such that its monomer component having an antimicrobial property is expensive and thereby making it uneconomical.
As another means to suppress the generation of odor, there has been proposed a process comprising mixing an organic antimicrobial agent such as a quaternary nitrogen-based compound with a water-absorbent resin (for example, see Patent Publication 2). However, there is a disadvantage in this process, such that the organic antimicrobial agent used is liable to cause inflammation when the organic antimicrobial agent is contacted with skin or mucous membrane.
Therefore, in recent years, as a composition for suppressing the generation of odor, there has been proposed a composition comprising an inorganic antimicrobial agent, in which an antimicrobial metal such as silver, copper or zinc is carried on an inorganic compound, and a water-absorbent resin (for example, see Patent Publication 3). The inorganic antimicrobial agent used in this composition has high safety, and its antimicrobial strength is maintained for a long time, so that the composition is suitable for the use of a hygienic material and the like. However, there are some problems in the inorganic antimicrobial agent, such that operating environments in the production of the absorbent article are worsened, since the inorganic antimicrobial agent has poor affinity to the water-absorbent resin, and therefore the inorganic antimicrobial agent generates dust in the production of an absorbent article such as disposable diaper.    Patent Publication 1: Japanese Patent Laid-Open No. Hei 8-92020    Patent Publication 2: Japanese Patent Laid-Open No. Hei 2-1265    Patent Publication 3: Japanese Unexamined Patent Publication No. 2001-505237